Hope for the Eastern Hog-nosed Snake

In the last 20 years, the eastern hog-nosed snake’s numbers have dropped to 7,500 and it has been listed as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Moreover, the eastern hog-nosed snake (Heterodon platirhinos) became extirpated from eight per cent of its occurrences in Ontario, and a whopping 35 per cent of its occurrences in the province are now considered historical or unconfirmed.

The Canadian Wildlife Federation’s Endangered Species Program recently gave $16,000 to Associate Professor Gabriel Blouin-Demers and MSc Candidate Laura Robson of the Department of Biology at the University of Ottawa to study the snake’s habitat selection patterns in the hopes of making new strides in conserving the species.

Losing GroundThe eastern hog-nosed snake scouts out habitats with sandy soil and open woods, fields and forests. It’s also been known to seek out abodes by the water and can often be spotted amid driftwood on beaches. There are two hot spots where the hog-nosed snake can be found: the Carolinian region of southwestern Ontario and the Great Lakes-St. Lawrence region of central Ontario. But not so long ago, this serpent slithered through Halton, Peel, York, Pelee Island and Point Pelee National Park. Unfortunately for this snake, its favoured habitats are prime real estate for agriculture and water-related recreation. Moreover, in southwestern Ontario, housing development and associated road networks have also ushered the snake out of its habitat and onto roads, increasing mortality and habitat fragmentation.

On the Road Again If habitat loss is the primary cause of declines and losses of reptiles across the board, motor vehicles are a close second. This threat is only amplified by the mobile nature of the eastern hog-nosed snake. With houses going up in a snap and associated road networks (like the expansion of Highway 69) popping up across the Georgian Bay region, the snake is hard pressed to find a safe route in its home base. And the grass is not greener south of the Canadian Shield. This area has the highest density of roads per capita in the world. That’s bad news for the eastern hog-nosed snake. Researchers have found snakes living within half a kilometre of roads. And data shows that some eastern hog-nosed snakes actually avoid crossing roads because of the risk, thereby restricting their home range and fragmenting entire populations.

A Taste for ToadsSouth of the border, the eastern hog-nosed snake munches on toads, frogs, lizards, insects, amphibians, birds, molluscs, crustaceans and even turtles. But their northern comrades are a fussier bunch. Canadian eastern hog-nosed snakes are partial to toads and toads alone. As such, their range is entirely dependent on the health of the toad population—which, in recent years, has taken a turn for the worse. For example, a 2005 study found declines in the American toads of the Great Lakes basin region. As a result, it’s imperative to consider the habitats and health of American toads and also Fowler’s toads when considering the eastern hog-nosed snake’s ability to thrive in Canada.

How Blouin-Demers’ and Robson’s Research Fits InTracking snakes via radio-telemetry, the University of Ottawa’s Department of Biology is studying the eastern hog-nosed snake’s habitat selection patterns to identify what makes up critical habitat for the species, including nesting and hibernation sites. The research will also establish what constitutes the destruction of habitat through the snake’s Ontario range.